Flashcards in EXAM #2: ENDOCRINE PANCREAS ANATOMY Deck (36):
1
What are pancreatic islets embryologically derived from?
Endoderm
2
What hormone is secreted by Beta cells in the pancreas?
Insulin
3
What hormone is secreted by Alpha cells in the pancreas?
Glucagon
4
What hormone is secreted by Delta cells in the pancreas?
Somatostatin
5
What is contained in an immature secretory vesicle of the beta cells? What happens in this vesicle?
Proinsulin, which is cleaved into Insulin and Protein C
6
How does Clathrin differentiate between an immature vesicle and mature vesicle in the Beta cell?
Immature= clathrin coated
Mature= no clathrin
7
Which has a longer half-life, insulin or protein c?
Protein C
8
Is GLUT-2 dependent or independent of insulin?
Independent
9
What is the mechanism of insulin release from the beta cells?
1) Glucose in via GLUT-2
2) Glycolysis increases ATP
3) ATP binds K+ sensitive channel, inactivating it and leading to membrane depolarized (Sulfonylurea Receptor)
3) Ca++ enters voltage gated channels
4) Insulin is released via exocytosis
10
What drugs target the K+ channel necessary for insulin release?
Sulfonylurea class drugs i.e.
- Gliclazide
- Glimepiride
11
What transporter is necessary for glucose entry in target cells?
GLUT-4
12
Is GLUT-4 dependent or independent of insulin?
Dependent
13
What does insulin do to target cells?
- Causes insertion of GLUT-4 transporters into membrane
- Glucose enters the cell
14
What is the embryologic origin of the adrenal cortex?
Mesoderm
15
What is the embryologic origin of the adrenal medulla?
Neural crest cells
16
What is required for the differentiation of neural crest cells to chromaffin cells in the adrenal medulla?
Cortisol
17
What is the mnemonic to remember the parents vessels of the suprarenal arteries?
IPAR
Inferior phrenic= superior suprarenal a.
Aorta= middle suprarenal a.
Renal= inferior suprarenal a.
18
What is the origin of the cortical and medullary arteries?
Supracapsular arterial plexus (plexus under the capsule from the suprarenal a)
19
What capillaries receives the hormones from the adrenal cortex?
Sinusoidal capillaries in the cortex
20
Where does the right suprarenal vein empty?
IVC
21
Where does the left suprarenal vein empty?
Left renal vein
22
What are the three zones of the adrenal cortex?
GFR:
Glomerulosa
Facsiculata
Reticularis
23
What is the mnemonic to remember the hormones released from the zones of the adrenal cortex?
Salt, sugar, sex
Aldosterone= G
Cortisol= F
Androgens= R
24
Histologically, what do you NOT see in the adrenal cortex would be expected b/c of the glands high output of secretory products?
Secretory vesicles; steroid hormones diffuse across membrane unlike peptide hormones
25
ACTH has a stimulatory effect on which two parts of the adrenal cortex?
Fasiculata and reticularis, NOT Glomerulosa
26
What is the expected gross finding in the setting of ACTH excess i.e. Cushing's?
Cortical hypertrophy contributed by Fasiculata and Reticularis ONLY
27
What hormone has a major inhibitory effect on ACTH and cortisol secretion?
Glucocorticoids
28
What segmental levels of the SNS innervate the adrenal medulla?
T8-L1
29
Catecholamines are derived from what amino acid?
Tyrosine
30
List the steps in catecholamine synthesis?
1) Tyrosine
2) DOPA
3) Dopamine
4) NE
5) Epinephrine
31
What enzyme converts NE to Epi? What hormone activates this enzyme?
Phenylethanolamine-N-methyltransferase, which requires cortisol
32
In catecholamine synthesis, which is the only product that is NOT made in the cytoplasm?
NE
*Dopamine to NE enzymatic step occurs in the secretory vesicle
33
When catecholamine synthesis increases, what binding protein also increases?
Chromogranin
34
What is the Organ of Zuckerkandl?
Ectopic adrenal-medulla tissue in the region of the aortic bifurcation
35
A tumor of the Organ of Zuckerkandl i.e. a pheochromocytoma, is expected to increase the output of what?
Norepinehprine
*Without cortisol from the adrenal cortex, cannot convert NE to Epi
36